krusty et al., I live near a military base (in fact, the town probably would not be here were it not for the base), and I find a lot of Thorsen tools in the second hand market. I have figured one reason for so much of the Thorsen brand would be the military 'surplus'. (surplus in quotes because I'm not sure that is the correct term for tools that an airman has walked off with and sold to a pawn shop, maybe so, I don't know. Maybe the air force was going to throw them out ... but that is a different discussion, I digress). Anyway, I see Thorsen products maybe 5:1 more than any other brand except Craftsman of course.
The point of my long winded story is, that I haven't seen a ratchet like yours before, other than the JC Penny model in the GG thread and I do think I have seen a Japanese Craftsman copy that had a similar look, but I don't recall where. The military surplus is a good guess, but I would have thought I'd have seen one in my travels if the USAF bought them in quantity. Another guess might be for a regional discount hardware or parts store contract deal. I also think oily's guess is good; think it is possible that someone found some spare guts that fit the Japanese handle they had on hand.
In any case, it is an unusual piece.
*edit: I thought oily had guessed japanese as a possibility in his post above. Not so.